1. Field of the Invention
The invention relates to a strip conductor, which has at least one curved section comprising a strip conductor layer.
2. Summary of the Prior Art
Strip conductors are used in electronic circuits to connect electrical components with one another. Furthermore, it is known to arrange strip conductors in the form of a meandering resistance strip to fix a defined resistance on an electronic circuit. In the case of a meandering strip conductor, current density is distributed unevenly in the region of the curves, which may cause voltage peaks that lead to damage of the strip conductor.
To avoid disproportionately high voltages, which occur, for example, when lightning strikes, it is already known from the prior art to construct the strip conductor curves in the form of a low-resistance section of the strip conductor. The construction of the low-resistance section of the strip conductor offers the advantage that a raised voltage does not damage the low-resistance section of the strip conductor. The construction of the strip conductor curves in the form of low-resistance strip conductor sections has the disadvantage, however, that for a given resistance value the overall strip conductor length is extended, because the low-resistance strip conductor sections in the region of the strip conductor curves do not contribute to the effective resistance length.
The invention is based on the problem of producing a strip conductor with a strip conductor curve, which is of simple construction and at large voltages is protected against damage in a region of the curve. This problem is solved by a strip conductor as defined above, which in accordance with the invention, is characterised in that at least one region of the curved section is provided with an additional layer, having a smaller resistivity than the strip conductor, and the at least one region is constructed such that the resistance on tracks of different radii of curvature is approximately equalized. An important advantage of the invention is that an additional or second layer, which has a smaller resistivity than the material of the strip conductor, is applied to a curved section of the strip conductor in at least one region. The region is constructed so that resistance strips having different radii of curvature have an approximately equal resistance. This provides a strip conductor that is protected against voltage peaks in the region of the curve.
Further advantageous embodiments are described herein. Preferably, one region has a form that extends from a curve inside to a curve outside, the width of the form increasing from the curve inside to the curve outside.
In a preferred embodiment of the invention, only one region of the curved section has the second layer. In this way, the curved section to which no second layer has been applied also contributes to the effective resistance length, so that the strip conductor as a whole can be made shorter to present a fixed resistance, thereby saving area.
A preferred embodiment of the region in which the second layer is formed comprises the form of a segment of a circle, the midpoint of the circle being arranged on the curve inside of the curved section.
Preferably, the second layers are formed in several regions of the section, in order to achieve a current distribution that is as uniform as possible over the width of the strip conductor and at the same a time to obtain a maximum contribution of the curved section to the effective resistance length.
FIG. 1 schematically shows a meandering resistance strip on an electronic circuit,
FIG. 2 schematically shows a section of the meandering resistance strip in the region of a curve,
FIG. 3 schematically shows a ceramics plate, to which the second layer and the strip conductor are applied, and
FIG. 4 schematically shows a strip conductor having a second layer beneath it for the entire curve region.